https://www.epo.org/en/node/which-situations-should-i-use

In which situations should I use the Contingency Upload Service?

This service is offered as a contingency, in the unlikely event that the applicant must submit documents to the EPO urgently and the standard EPO filing tools or EPO account are not available to support this. A direct link to the Contingency Upload Service will be published on EPO’s outage pages in the event of an unavailability of the EPO filing tools.

Applicants are strongly encouraged to use the EPO online services and filing tools whenever possible to benefit form the business validations and the accelerated processing of submissions that originate from these tools.